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 ###Instrução: Qual fabricante tem um ano de fabricação de 1923?
 ###Tabelas: CREATE TABLE head_to_head (head_to_head_id AUTO_INCREMENT PRIMARY KEY, Tournament VARCHAR, Matches INT, Wins Olimpia INT, Empates INT, Wins Cerro INT, Goals Olimpia INT, Goals Cerro INT) CREATE TABLE deficit_spending (deficit_spending_id AUTO_INCREMENT PRIMARY KEY, End of Fiscal Year INT, Gross Debt in $Billions undeflated Treas. INT, as % of GDP Low-High VARCHAR, Debt Held By Public ($Billions) INT, as % of GDP (Treas/MW, OMB or OMB/MW) INT, GDP $Billions OMB/BEA est.=MW.com VARCHAR) CREATE TABLE class_h:_4-6-2 (class_h:_4-6-2_id AUTO_INCREMENT PRIMARY KEY, Class VARCHAR, Wheel arrangement VARCHAR, Fleet number(s) VARCHAR, Manufacturer VARCHAR, Year made VARCHAR, Quantity made VARCHAR, Quantity preserved VARCHAR) CREATE TABLE 1860s (1860s_id AUTO_INCREMENT PRIMARY KEY, Year INT, Number of tropical storms INT, Number of hurricanes INT, Number of major hurricanes INT, Deaths VARCHAR, Strongest storm VARCHAR) CREATE TABLE passengers_carried_in_2011 (passengers_carried_in_2011_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Airline VARCHAR, Country VARCHAR, Remarks VARCHAR, Alliance VARCHAR)  
SELECT Manufacturer FROM class_h:_4-6-2 WHERE Year made = 1923